@misc{10481/109743,
year = {2021},
url = {https://hdl.handle.net/10481/109743},
abstract = {Signalling through chemosensory pathways is typically initiated by thebinding of signal molecules to the chemoreceptor ligand binding domain(LBD). The PcaY_PP chemoreceptor from Pseudomonas putida KT2440 ischaracterized by an unusually broad signal range, and minimal requisitesfor signal binding are the presence of a C6-membered ring and that of acarboxyl group. Previous studies have shown that only some of the multi-ple signals recognized by this chemoreceptor are of apparent metabolicvalue. We report here high-resolution structures of PcaY_PP-LBD in theabsence and presence of four cognate chemoeffectors and glycerol. Thedomain formed a four-helix bundle (4HB), and both ligand binding sites ofthe dimer were occupied with the high-affinity ligands protocatechuate andquinate, whereas the lower-affinity ligands benzoate and salicylate werepresent in only one site. Ligand binding was verified by microcalorimetrictitration of site-directed mutants revealing important roles of an arginineand number of polar residues that establish an extensive hydrogen bondingnetwork with bound ligands. The comparison of the apo and holo struc-tures did not provide evidence for this receptor employing a transmem-brane signalling mechanism that involves piston-like shifts of the finalhelix. Instead, ligand binding caused rigid-body scissoring movements ofboth monomers of the dimer. Comparisons with the 4HB domains of theTar and Tsr chemoreceptors revealed significant structural differences.Importantly, the ligand binding site in PcaY_PP-LBD is approximately8  A removed from that of the Tar and Tsr receptors. Data indicate a sig-nificant amount of structural and functional diversity among 4HBdomains.},
organization = {Spanish Ministry for Science, Innovation and Universities, PID2019-103972GAI00},
organization = {Spanish Ministry of Economy and Competitiveness, BIO2016-74875-P and BIO2016-76779-P},
publisher = {Wiley},
keywords = {Chemoreceptors},
keywords = {Chemotaxis},
keywords = {Ligand recognition},
title = {The structural basis for signal promiscuity in a bacterial chemoreceptor},
doi = {10.1111/febs.15580},
author = {Gavira Gallardo, José Antonio and Matilla, Miguel A. and Fernández Rodríguez, Matilde and Krell, Tino},
}